09年末逻辑狗狗里，那个幼虫的gwd题，能帮解释下吗？

zengshiyu

Lyme disease is caused by a bacterium transmitted to humans by deer ticks. Generally deer ticks pick up the bacterium while in the larval stage from feeding on infected whitefooted mice. However, certain other species on which the larvae feed do not harbor the bacterium. Therefore, if the population of these other species were increased, the number of ticks acquiring the bacterium and hence the number of people contracting Lyme disease would likely decline.

Which of the following, if true, most strengthens the argument?

Ticks do not suffer any adverse consequences from carrying the bacterium that causes Lyme disease in humans.

There are no known cases of a human’s contracting Lyme disease through contact with white-footed mice.

A deer tick feeds only once while in the larval stage.

A single host animal can be the source of bacterium for many tick larvae.

None of the other species on which deer tick larvae feed harbor other bacteria that ticks transmit to humans

题目读的不是很明白，还有各个选项大家帮忙解释下吧！

答案是C

阿彻

我想问E为什么不对？

yamakillua

E选项的other bacteria是无关信息。所以该选项排除

zengshiyu

E选项的other bacteria是无关信息。所以该选项排除

-- by 会员 yamakillua (2009/12/9 13:27:19)

楼上可否帮忙解释一下题目呢？

sprtng

Lyme disease is caused by a bacterium transmitted to humans by deer ticks. Generally deer ticks pick up the bacterium while in the larval stage from feeding on infected whitefooted mice. However, certain other species on which the larvae feed do not harbor the bacterium. Therefore, if the population of these other species were increased, the number of ticks acquiring the bacterium and hence the number of people contracting Lyme disease would likely decline.

Which of the following, if true, most strengthens the argument?

Ticks do not suffer any adverse consequences from carrying the bacterium that causes Lyme disease in humans.
跟问题无关
There are no known cases of a human’s contracting Lyme disease through contact with white-footed mice.
跟问题无关 （有点纠结， 不过文章没谈到人直接接触白脚小鼠～ 所以忽略）
A deer tick feeds only once while in the larval stage.
就算增加了其他小鼠的数量， 如果幼虫各种小鼠都去咬一口， 不管其他小鼠的数量有多少， 只要咬了whitefooted mice那就会变carrier~strengthen撒
A single host animal can be the source of bacterium for many tick larvae.

weakens the argument
None of the other species on which deer tick larvae feed harbor other bacteria that ticks transmit to humans
无关。
题目读的不是很明白，还有各个选项大家帮忙解释下吧！

答案是C

-- by 会员 zengshiyu (2009/12/9 12:46:08)

俺的一点愚见 =- =

zengshiyu

通过deer ticks传送细菌到人体使人得L病。deer ticks是在细菌的幼虫阶段给它喂食whitefooted mice来选择拿什么样细菌传送到人体的。但是如果喂食其他食物给细菌就不会产生这种细菌。所以如果其他细菌种类增多，感染L病的人就会减少。 问加强。答案是：细菌只有一次幼虫阶段。。。
想问下C为啥支持啊？

yamakillua

Lyme这个疾病是由于deer扁虱将病毒传递给人类所引起的，通常，deer扁虱在幼虫阶段，通过食用受到感染的白脚老鼠获得的这种病毒。然而，它们在幼虫阶段食用的其他食物并不含有这种病毒。所以，如果其他食物的数量增加，扁虱获得的病毒就会减少，从而得Lyme这种病的人就会减少。
LZ凑合看把，本人英文功有限，这是我的理解。不是能不能帮助到LZ

zengshiyu

Lyme disease is caused by a bacterium transmitted to humans by deer ticks. Generally deer ticks pick up the bacterium while in the larval stage from feeding on infected whitefooted mice. However, certain other species on which the larvae feed do not harbor the bacterium. Therefore, if the population of these other species were increased, the number of ticks acquiring the bacterium and hence the number of people contracting Lyme disease would likely decline.

Which of the following, if true, most strengthens the argument?

Ticks do not suffer any adverse consequences from carrying the bacterium that causes Lyme disease in humans.
跟问题无关
There are no known cases of a human’s contracting Lyme disease through contact with white-footed mice.
跟问题无关 （有点纠结， 不过文章没谈到人直接接触白脚小鼠～ 所以忽略）
A deer tick feeds only once while in the larval stage.
就算增加了其他小鼠的数量， 如果幼虫各种小鼠都去咬一口， 不管其他小鼠的数量有多少， 只要咬了whitefooted mice那就会变carrier~strengthen撒
A single host animal can be the source of bacterium for many tick larvae.

weakens the argument
None of the other species on which deer tick larvae feed harbor other bacteria that ticks transmit to humans
无关。
题目读的不是很明白，还有各个选项大家帮忙解释下吧！

答案是C

-- by 会员 zengshiyu (2009/12/9 12:46:08)

俺的一点愚见 =- =

-- by 会员 sprtng (2009/12/9 13:36:07)

这个C解释的不错，大家还有什么好的建议吗？

yamakillua

我对C选项的理解是，幼虫只吃一次，因为虽然在文中说other species的数量上升，但并没有涉及到白脚老鼠的数量。如果幼虫在持续进食，那么other species的数量会减少，从而幼虫还是不可避免的食用白脚老鼠，扁虱获得病毒不会因此而减少，结论不成立

AllenZX

之前好像回过这题.
大概可以这样具体化一下: 假如原来感染的mice占1/3, 那么其他spicies增加会使mice的比率减少,假如到1/4, 这样来说结论是成立的, lava确实感染的机率降低.   但是如果lava不只吃一次的话, 假如吃两次, 那他在两次中只要有一次吃到感染的就会感染, 那么这样的机率是1-3/4*3/4(1-两次都没吃到感染的机率) , 吃三次就是1-3/4*3/4*3/4.. 再吃就再乘. 后面的数越乘越小, 机率就趋近于100%. 这样结论是不成立的.  所以要用C来排除这个可能.